How many troops were deployed in World War 1?

During World War I, approximately 65 million military personnel were mobilized from various countries involved in the conflict. The major powers included the Allies, such as France, the United Kingdom, Russia, and the United States, and the Central Powers, including Germany, Austria-Hungary, and the Ottoman Empire. Troop deployments varied significantly, with millions seeing combat on the Western and Eastern Fronts. The war resulted in unprecedented casualties and reshaped global military dynamics.